Switch mechanism



June 14, 1960 D.-\N. LAVIANA SWITCH MECHANISM Filed July 30, 1958INVENTOR. 00/0110 ll MV/IM/I BY I l A H/J ATM/1WD United States Patent2,941,051 swrrcn MECHANISM Donald W. Laviana, Pittsford, N.Y., asslgnorto General Motors Corporation, Detroit, Micln, a corporation of DelawareFiled July 30,1958, Set. No. 151,910

1 Claims. c1. 200-38 This invention relates to switch and controlmechanisms such as may be used in program timers.

In the design of program switches, some means is usually employed toeffect a fast action of the make and break of the contacts to avoidexcessive contact deterioration. A popular means of accomplishing suchfast act-ion is to advance the actuating earns in quick steps through anescapement. Although this jump type switch works satisfactorily whenproperly adjusted, considerable difficulty is experienced in theirmanufacture due to a multiplicity of tolerances which affects therelation of the switches and their operating cams.

It is an object of this invention to provide a switch actuatingarrangement in which there is eliminated the necessity of individualswitch adjustment andwhich allows larger manufacturing toleranceswithout comprising accuracy of timing. I

It is another object of this invention to provide fast making andbreaking of contact mechanisms when a slow, constant speed cam drive isprovided.

These and other objects are attained in the form shown in the drawingsin whicha constantly rotating slow speed cam is provided with abruptperipheral drops to suddenly move a spring pressed cam follower. Thefollower is provided with a saw-tooth cam surface which eithercooperates with a guideway or with a V-shaped hump on a spring contactmember to move in either form a spring contact member between normallystationary contacts.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred embodiment of the present invention isclearly shown.

In the drawings:

Figure 1 is a perspective fragmentary view of a program timer embodyingone form of my improved switch mechanism; and

'Figure 2 is a fragmentary sectional view of a program timerillustrating a modified form of my improved switch mechanism.

Referring now' to the drawings and more particularly to Fig. 1, there isshown a timer motor 20 which either constantly or intermittently rotatesthe drive pinion 2. The drive pinion 2 meshes with .and rotates a gearwheel 1 rotatably mounted on the'c am shaft 3. A wound spring clutch 4connects the gear 1 to the shaft 3 when the gear 1 is rotated in theclockwise direction and disconnects the gear 1 from the shaft 3 when theshaft 3 is turned in the clockwise direction. A spring detent engagesthe teeth of the gear wheel 1 to prevent counterclockwise rotationthereof. Fixed to the shaft 3 is a cam 5 having a section 21 of maximumradius and successively reduced sections 22, 24 and 26 of successivelyreduced radius, with sharp drops between the sections. Between thesections 26 and '21 there is provided a more gradual incline 28.

A cam follower or switch operator 7 is normally held in engagement withthe periphery of the cam 5 by a of the housing of the timer.

cantilever arranged looped wire spring 8 extending through a notch inthe top of the follower 7 to urge it downwardly. The left edge of thefollower 7 is provided with'a sawtooth cam surface 30. The cam follower7 is slidably mounted in a guide means 9 formed as a part The guidemeans 9 is provided with a groove 32 slidably receiving the follower 7and having a sawtooth cam surface 34 in the bottom of the groove 32which is complementary to the cam surface 30 upon the follower 7. Aspring switch blade 36 has a spring bias against the adjacent venticaledge of the follower 7 to hold the cam surfaces 34 and 30 in engagement.The spring switch blade 36 is anchored to a housing portion 38. Theopposite end of the spring switch blade 36 carries a double contact 40adapted to make contact at opposite limits of its movement with the theblade 36 stationary contacts 42 and 44. The height of the fiat top sawteeth cam surfaces and 34 is just suflicient to pro vide movement of thedouble contacts between the contacts 42 and 44.

When the tops of the teeth of the surfaces 30 and 34 are in contact, thecam follower 7 and the blade 36 are cammed to the right sufliciently tocause engagement of the contacts 40 and 44. When the saw teeth of thesurfaces 30 and 34 are exactly in mesh, the spring effect of will carrythe follower 7 and the contact 40 to the left extremity of theirmovement to make con-. tact with the contact 42. When the saw teeth arein contact intermediate the top and the bottom, the blade vent currentflow to either contact.

36 will be held between the contacts 42 and 44 to pre The radii of thedifferent segments 21, 22, 24 and 26 may be so chosen to hold the teetheither with the tops in engagement or nested, or at intermediate pointsto provide the switch positions desired. The ramp 28 returns thefollower 7 to its upper position. The knob 46 fastened to the right endof the shaft 3 may be used to manually turn the shaft 3 and the cam Sinthe clockwise direction.

In Figure 2, a cam is fixed to a shaft 53 and similarly includessections 57, 59, 61 and 63 of progressively reduced radii. The junctionsof the sections are provided by sharp drops. Between the sections 63 and57 there is provided a gradual lifting ramp 65. This cam 55 and theshaft 53 may be similar to the corresponding mechanism in Figure 1 andmay be similarly provided with a drive mechanism and knob.

A cam follower 67 is provided with a foot 69 held in engagement with theperiphery of the cam 55 by a tension coil spring 71. The follower 67 issomewhat T.- shaped and is provided with a sawtoothed cam surface 1 73on its lower edge. The upper edge of the follower 67 is received withinthe notches 75 in the guide members 77.

Beneath the cam follower 67 is a spring blade 79 provided with ananchorage 81 at one end and a double contact 83 at the opposite end. Thedouble contact 83 operates between the upper and lower stationary switchcontact members 85 and 87. At an intermediate point of the switch blade79 there is provided an inverted V shaped hump 89' substantiallycomplementary to the notches between the saw teeth of the cam surface73. When the hump 89 rests on one of the tips of the saw teeth, as shownin Figure 2, the switch blade 79 will be pushed downwardly to move thecontact 83 into engagement with the contact 87. When the cam moves thefollower 67 so that the hump 89 is in any of the notches between the sawteeth of the cam surfaces 73, the spring force of the blade 79 willcarry the contact 83 into engagement with the upper stationary contact85. When the cam 55 moves the follower 67 so that the hump 89 is at anintermediate point upon any of the teeth of the ens on cam surface 73,the contact '83 will be held at an intermediate point out of "contactwith both'the upper and lower contacts 85 and 87.

As described in Figure l, the radii .ofthe cam 55-ma y be chosen so asto-movethe cam'fo1lower 67 to present cither'ahi'gh, low. 'orintermediate surface of the cam surface :7 3 in engagement withz'thehump'89 appropriately hold "the :switch blade in either lower, upper or.intermediateipositi'ons :as desired.

While the embodiment of the present invention ashorein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted.

'What is claimed is as follows;

1. Aswitch mechanism including an actuating cam, a follower contactingand moved by said cam in .a general direction, guide "means for guidingsaid .follower in said general 'directio'nin 'ac'cordanc'eiwiththemovement provided by "said cam, said follower being provided "with a'cam'surface extending .generally parallel to said general "directionsbut having 'at least three successive distinct deviations'laterally ofsaid general direction, and aswitch means operated'in accordance'witheach of the deviations of'the cam surface of saidfollower'relettiVetofthe movement of said follower.

2. A switch mechanism 'including'an actuating camhav- 'ing a cam surfacewith at least three different distinct actuating sections "at differentprogressively decreasing distances from a base line, a followercontacting and moved in at least three distinctprogressive "movements"by 'said'cam and cam surface according to the contourof said surface,guide means for guiding "said follower in a general "direction inaccordance withthe"movement provided by said 'cam, said"follower'alsohaving'a fcam sur- "face extending at angles'to said'general directiontopromeans in an intermediate "position or positions on either sideDfSald intermediate: position.

.5. A switch mechanism.:including -.an actuating oam having a camsurface with at least three different distinct actuating sections, afollower contacting and moved by said cam and cam surface to'threecorresponding different distances,'=gguide means for guiding saidfollower in a general direction in accordance with the movement providedby said cam, said follower having a cam surface with at least threedeviations extending alternatelyv "at "angles 'tosaid general direction,and a switch'means havinga follower projection in contact with-the saidfollower cam surface operable to three different positions in responseto them'ovem'ent of said follower.

A switch mechanism including an actuating cam having a -cam surface with*a'tleast three different distinct actuating sections, a followercontacting and moved-by s'aidcam' in 'at least three distinct movementsin a general direction, said follower-having a cam surface provided'with alternating deviations relative to said general direction, a guidemeans having a complementary cam surface in contact at one point withsaid "cam surface ofsaid follower, 'andsdoubl'e throw switch means alter'n'ate'd a plurality of times lateral-lyof said general "diIE/b';

tion by thedistinct movements of 'said' follower relative to saidguidemeans.

7. A switch mechanism including an actuating cam, a follower contactingand 'moved by said cam in a general direction,- saidfollower having acam surface provided with at least three distinctly separate deviations3'. A switch mechanism including an actuating means,

a follower contacting and moved by saidactua'tingmeans, guiding meansfor guiding said follower 'in a general direction in accordance withthemovement provided by'said cam," said follower having a sawtoothed typeof cam surface having at le'asttwo teeth extending generally'parallel tosaid general direction, a'three position switch means operated inaccordance with deviations of the teeth of said sawtoothed camsurfacerelative to said "general direction, said actuating-means havingmeans for holding said sawtooth cam surface "in three distinctlydifferent positions relative to said switch means for holding saidswitch means in three different positions.

4. A switch mechanism including an actuating means,

a follower'contacting and moved by said actuatingm'eans,

' relative to said general direction, guide means having a complementarycam surface in contact at one point'with said cam surface of saidfollower, a laterally movable switch blade operably connected to saidfollower'for distinct movements laterally of said general directioncorresponding to' said distinctly separate deviations, and spacedrelatively stationary contacts laterally-located on opposite sides ofsaid-switch blade and engaged by said switch blade at 'thecxtremityiofits movements.

References Cited in the'file of this patent UNITED STATES PATENTS1,626,659 Austin et a1. May 3, 1927 1 ,842,371 Harrison Ian. 19, 19322,018,958 Jones et a1. Oct. 29, 1935 2,128,427 Means Aug. 30, 19382,231,218 "Palmer Feb. 11, 1941 2,814,683 Wharton Nov. '26, 1957 FOREIGNPATENTS I 487,658 Great Britain June 23, 1938 827,608 Germany Jan; "10,1952 "929,910 Germany 'July 7, 1 955

